The discussion of any work, publications, sales, or activity anywhere in this submission, including in any documents submitted with this application, shall not be taken as an admission that any such work constitutes prior art. The discussion of any activity, work, or publication herein is not an admission that such activity, work, or publication existed or was known in any particular jurisdiction.
Microfluidic cell culture is a promising technology for applications in the drug screening industry. Key benefits include improved biological function, higher-quality cell-based data, reduced reagent consumption, and lower cost. High quality molecular and cellular sample preparations are important for various clinical, research, and other applications. In vitro samples that closely represent their in vivo characteristics can potentially benefit a wide range of molecular and cellular applications. Handling, characterization, culturing, and visualization of cells or other biologically or chemically active materials (such as beads coated with various biological molecules) has become increasingly valued in the fields of drug discovery, disease diagnoses and analysis, and a variety of other therapeutic and experimental work.
Mammalian cell culture is particularly challenging, particularly for maintaining effective solid aggregates of cells in culture. Advances have been made by adapting various microfabrication and microfluidic technologies to cell culture, though there remains an ongoing need for a device that can be economically manufactured and used to provide effective cell culture.
Publications and/or patent documents that discuss various strategies related to cell culture using microfluidic systems and related activities include the following U.S. patent applications and non-patent literature, which, along with all citations therein, are incorporated herein by reference for all purposes. A listing of these references here does not indicate the references constitute prior art.    Cytoplex, Inc. U.S. Pat. No. 6,653,124 “Array-based microenvironment for cell culturing, cell monitoring and drug-target validation.”    Cellomics, Inc. U.S. Pat. No. 6,548,263 “Miniaturized cell array methods and apparatus for cell-based screening.”    Fluidigm, Inc. Published Application 20040229349 (Nov. 18, 2004) “Microfluidic particle-analysis systems.”